JP2005158530A - Fuel cell assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell assembly capable of effectively maintaining temperature in a housing. <P>SOLUTION: A plurality of fuel cell cells 62 are housed in a housing 2, and heat storage walls 44a, 44b, 44e, 44f are arranged around a cell assembly of the fuel cell cells 62 in the housing 2, and heat-insulating walls 4, 6, 8, 9 are arranged on outside faces of the housing 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell assembly, and more particularly to a fuel cell assembly suitably used for home use and store use having a power generation performance of 7 kW or less.

  In recent years, various fuel cell power generation systems such as solid polymer type, phosphoric acid type, molten carbonate type, and solid electrolyte type have been proposed as next-generation energy. In particular, the solid oxide fuel cell power generation system has an operating temperature as high as 700 to 1000 ° C., but has advantages such as high power generation efficiency and use of exhaust heat, and research and development are being promoted.

In a typical example of a fuel cell power generation system, as disclosed in the following Patent Document 1, a power generation chamber is defined in a housing, and a power generation unit including a cell stack is disposed in the power generation chamber. An assembly is provided. The power generation chamber is provided with an oxygen-containing gas supply path for supplying oxygen-containing gas and a fuel gas supply path for supplying fuel gas.
JP 2000-149976 A

  In a conventional solid oxide fuel cell assembly, in order to maintain a high power generation temperature, the power generation chamber is surrounded by a heat insulating material to prevent a decrease in the power generation temperature, but the fuel cell operation is not limited to a steady load operation. Although partial load operation according to demand-side required power is also effective, there is a problem that it is difficult to maintain the temperature in the housing in partial load operation with a small amount of heat generation.

  An object of this invention is to provide the fuel cell assembly which can maintain the temperature in a housing effectively.

  As a result of intensive investigations on the above problems, the present inventor has arranged heat storage members inside and outside the housing constituting the fuel cell assembly, and in particular, stored heat around the cell assembly in the housing. The present invention finds that the temperature inside the housing can be effectively maintained even during partial load operation with a small amount of heat generated by arranging a heat shielding member made of a material and arranging a heat shielding member made of a heat insulating material outside the housing. It came to.

  That is, the fuel cell assembly according to the present invention includes a plurality of fuel cells accommodated in a housing, and is provided with a heat shield in the housing, around the cell assembly of the fuel cells, and on the outer surface of the housing. It is characterized by arranging members. In such a fuel cell assembly, since the heat shielding member is disposed inside and outside the housing, the temperature inside the housing can be effectively maintained even during partial load operation with a small amount of heat generation.

  Moreover, the fuel cell assembly of the present invention is characterized in that a heat shield member is disposed in the housing so as to surround the cell assembly. In such a fuel cell assembly, since the heat shield member is disposed so as to surround the cell assembly, the power generation temperature can be more effectively maintained.

  Furthermore, the fuel cell assembly of the present invention is characterized in that the heat shield member arranged in the housing is made of a heat storage material, and the heat shield member arranged on the outer surface of the housing is made of a heat insulating material. In such a fuel cell assembly, high temperature heat can be stored by the heat storage material arranged around the fuel cell at the time of steady load operation of the fuel cell, and heat dissipation to the outside can be effectively suppressed, Furthermore, heat dissipation can be more effectively suppressed by a heat shielding member made of a heat insulating material arranged on the outer surface of the housing, and heat can be dissipated from the heat shielding member made of a heat storage material during partial load operation with a small amount of heat generation. The power generation temperature can be effectively maintained.

  The fuel cell assembly of the present invention is characterized in that a gas flow path is disposed between the heat shield members inside and outside the housing. In such a fuel cell assembly, heat loss from the gas flow path to the outside can be reduced.

  Further, the fuel cell assembly of the present invention is characterized in that a combustion gas discharge channel and a gas supply channel are arranged between the heat shield members inside and outside the housing to constitute a heat exchange part. In such a fuel cell assembly, the high-temperature combustion gas and the low-temperature introduction gas are heat-exchanged by the heat exchanging unit, so that the low-temperature introduction gas is preheated, so that the high-temperature power generation temperature can be maintained and the combustion is performed. Heat dissipation to the outside by gas can be suppressed. Since the volume ratio of the fuel gas used for power generation of the fuel cell and the oxygen-containing gas such as air is larger in the oxygen-containing gas, the supply gas that exchanges heat with the combustion gas in the counterflow is preferably an oxygen-containing gas.

  Furthermore, the fuel cell assembly of the present invention is characterized in that the density of the heat storage material is larger than that of the heat insulating material. In such a fuel cell assembly, since the heat capacity of the heat storage material is large, the power generation chamber surrounded by the heat storage material that should maintain the power generation temperature can be effectively maintained at a high temperature.

  Further, by enclosing the outside of the housing with a heat insulating material, external heat loss through the housing can be reduced, and heat exchange in the housing portion can be effectively functioned.

  The fuel cell assembly of the present invention is used for distributed power generation. For example, a fuel cell assembly used for a household fuel cell system having a power generation performance of about 1 kW or a store fuel cell system having a power generation performance of 7 kW or less is small in size, and the fuel cell assembly is self-sustaining. Therefore, the present invention can be used effectively.

  In the fuel cell assembly of the present invention, by disposing the heat shield member inside and outside the housing, in particular, a heat shield member made of a heat storage material is arranged around the cell assembly in the housing, and the outside of the housing. By disposing a heat-insulating member made of heat insulating material to the heat storage material, high-temperature heat around the cell can be stored by the heat storage material, and heat dissipation to the outside can be effectively suppressed together with the heat insulating material. In the fuel cell assembly for power generation, the power generation temperature can be effectively maintained even during partial load operation with a small amount of heat generation.

  Hereinafter, the fuel cell assembly of the present invention will be described with reference to FIGS. The illustrated fuel cell assembly includes a housing 2 having a substantially rectangular parallelepiped shape. The outer surface of the six wall surfaces of the housing 2 is a heat insulating wall (heat insulating member) formed of an appropriate heat insulating material, that is, the upper heat insulating wall 4, the lower heat insulating wall 6, the right heat insulating wall 8, the left heat insulating wall 9, and the front A heat insulating wall 10 and a rear heat insulating wall 11 are provided. A power generation / combustion chamber 12 is defined in the housing 2.

  The front heat insulation wall 10 and / or the rear heat insulation wall 11 is detachably or removably attached, and the front heat insulation wall 10 and / or the rear heat insulation wall 11 is detached or opened to access the power generation / combustion chamber 12. be able to. If desired, an outer wall, which may be made of a metal plate, can be disposed on the outer surface of each heat insulating wall.

  An air chamber (gas chamber) 16 is disposed at the upper end of the housing 2. The air chamber 16 is defined in a rectangular parallelepiped case 17 having a relatively small vertical dimension. The air chamber 16 communicates with the upper end of an air introduction pipe (gas supply means) 22 for sending air (oxygen-containing gas) toward the power generation / combustion chamber. There are a plurality of air introduction pipes 22 and the shape thereof may be a cylinder or a hollow plate structure. 1 and 2, a cylindrical air introduction tube 22 is shown. The air introduction pipe 22 is disposed between the cell stacks described later, and has an opening at the lower end portion of the cell, and air is ejected from the opening portion. The air introduction tube 22 is preferably made of a material having high heat resistance such as ceramics.

  The air chamber 16 is provided with a low-temperature gas supply means including a low-temperature gas supply pipe 18. The low-temperature gas supply pipe 18 penetrates the upper heat insulating wall 4 and extends to the outside.

  The low-temperature gas supply pipe 18 supplies the same type of gas as that supplied into the air chamber 16, that is, low-temperature air, into the air chamber 16. The air supplied through the low-temperature gas supply pipe 18 is It must be cooler than the temperature of the preheated air. In particular, about room temperature is desirable.

  As shown in FIG. 2, the low temperature gas supply pipe 18 is connected to a position of the air chamber 16 that cools the power generation units 56a, 56b, 56c, and 56d, that is, the central portion of the fuel cell assembly. In other words, the air introduction pipe 22 disposed between the power generation units 56a, 56b, 56c, and 56d has a low temperature so as to open at the position of the opposing case 17 side plate with respect to the center of the opening assembly to the case 17 side plate. A gas supply pipe 18 is provided.

  A heat exchanger 24 having a flat plate shape as a whole is disposed on both sides of the housing 2, more specifically, inside the right heat insulating wall 8 and inside the left heat insulating wall 9. Each of the heat exchangers 24 is constituted by a case 26 having a hollow flat plate shape extending substantially vertically.

  A partition plate 28 located in the middle in the lateral direction is disposed in the case 26, and the inside of the case 26 is partitioned into a discharge path 30 positioned on the inner side and an inflow path 32 positioned on the outer side. Three partition walls 34 and 36 are arranged in the discharge path 30 at intervals in the vertical direction. More specifically, in the discharge passage 30, the front edge is located rearwardly away from the front wall (not shown) of the case 26, but the rear edge is the rear wall (not shown) of the case 26. And a partition wall 36 whose front edge is connected to the front wall of the case 26 but whose rear edge is spaced forward from the rear wall of the case 26. Are alternately arranged, and thus the combustion gas discharge passage 30 is zigzag-shaped. If desired, a form other than the zigzag flow path may be used.

  Similarly, the three partition walls 38 and 40, that is, the front edges thereof are also spaced apart from the front wall (not shown) of the case 26 in the inflow path 32 with a space in the vertical direction. The rear wall is connected to the rear wall (not shown) of the case 26, and the front edge of the partition wall 38 is connected to the front wall of the case 26. The partition walls 40 spaced apart from the front are alternately arranged, and thus the inflow passage 32 is also zigzag-shaped. If desired, a form other than the zigzag flow path may be used.

  A discharge opening 42 is formed at the upper end of the inner wall of the case 26, and the discharge path 30 is communicated with the power generation / combustion chamber 12 through the discharge opening 42. In the illustrated embodiment, heat storage walls (heat shielding members) made of a heat storage material are arranged on the power generation / combustion chamber 12 side of the heat exchanger 24, that is, on the fuel cell side and above and below the fuel cell. Has been. That is, the right heat storage wall 44a, the left heat storage wall 44b, the front heat storage wall 44c and the rear heat storage wall 44d, the upper heat storage wall 44e, and the lower heat insulation wall 44f are arranged so as to surround the cell assembly. An opening 45 is formed in the upper part of the right heat storage wall 44 a and the left heat storage wall 44 b so as to be located at substantially the same height as the lower edge of the discharge opening 42, and the discharge opening 42 generates power through the opening 45. -It is connected to the combustion chamber 12.

The heat insulating walls 4, 6, 8, 9, 10, and 11 formed on the outer surface of the six wall surfaces of the housing 2 are formed of an alumina / silica general-purpose heat insulating material so as to surround the cell assembly. The heat storage walls 44 a, 44 b, 44 c, 44 d, 44 e, 44 f are formed from a heat insulating material having a higher alumina purity than the heat insulating materials 4, 6, 8, 9, 10. The heat insulating walls 4, 6, 8, 9, 10, 11 and the heat storage walls 44a, 44b, 44c, 44d, 44e, 44f may be formed of the same material, but the density of the heat storage material is larger than that of the heat insulating material. Is desirable. The heat insulating walls 4, 6, 8, 9, 10, 11 have a density of 0.26 g / cm ³ or less, and the heat storage walls 44a, 44b, 44c, 44d, 44e, 44f have a density of 0.32 g / cm ³ or less. The thermal conductivity of is preferably 0.1 to 0.4 W / (m · K).

  An inflow opening 48 is formed on the outer side of the upper wall of the case 26, and the inflow path 32 is communicated with the air chamber 16 through the inflow opening 48. The heat exchanger 24 and the inflow opening 48 constitute a gas supply channel. A double cylinder 50 (only the upper end portion is shown in FIG. 1) extending in the vertical direction is disposed behind each of the inflow passages 32. The double cylinder 50 is an outer cylinder member. 52 and an inner cylindrical member 54. The lower end of the discharge path 30 is connected to the lower end of the discharge path defined between the outer cylinder member 52 and the inner cylinder member 54, and the lower end of the inflow path 32 is defined in the inner cylinder member 54. Connected to the inflow channel.

  Thus, the configuration of the fuel cell assembly shown in the drawing is substantially the same as the fuel cell assembly disclosed in the specification and drawings of Japanese Patent Application No. 2003-295790 filed by the present applicant. Therefore, the details of the configuration described above are left to the specification and drawings of Japanese Patent Application No. 2003-295790, and the description thereof is omitted in this specification.

  Four power generation units 56a, 56b, 56c and 56d are arranged in the lower part of the above-described power generation / combustion chamber. The power generation units 56a, 56b, 56c, and 56d are respectively positioned between the air introduction pipes 22 described above. In other words, the air introduction pipe 22 is disposed between the power generation units 56a, 56b, 56c and 56d. 3 and 4 together with FIGS. 1 and 2, the power generation unit 56a includes a rectangular parallelepiped fuel gas case 58a extending in the front-rear direction (direction perpendicular to the paper surface in FIG. 1). .

  A cell stack 60a is mounted on the upper surface of the fuel gas case 58a that defines the fuel gas chamber. The cell stack 60a is configured by arranging a plurality of upright cells 62 extending in the vertical direction in the longitudinal direction of the fuel gas case 58a (that is, in the front-rear direction). As clearly shown in FIG. 5, each cell 62 includes an electrode support substrate 64, a fuel electrode layer 66 that is an inner electrode layer, a solid electrolyte layer 68, an oxygen electrode layer 70 that is an outer electrode layer, and an interconnector 72. Has been.

  The electrode support substrate 64 is a columnar plate-like piece that is elongated in the vertical direction, and the cross-sectional shape thereof has both flat surfaces and both sides of a semicircular shape. The electrode support substrate 64 is formed with a plurality (six in the illustrated example) of fuel gas passages 74 penetrating the electrode support substrate 64 in the vertical direction. Each of the electrode support substrates 64 is bonded to the upper wall of the fuel gas case 58a by, for example, a ceramic adhesive having excellent heat resistance.

  On the upper wall of the fuel gas case 58a, a plurality of slits (not shown) extending in the left-right direction are formed at intervals in a direction perpendicular to the paper surface in FIG. A fuel gas passage 74 is communicated with the fuel gas chamber according to each of the slits.

  The interconnector 72 is disposed on one side of the electrode support substrate 64 (upper surface in the cell stack 60a in FIG. 5). The fuel electrode layer 66 is disposed on the other surface (the lower surface in the cell stack 60a of FIG. 5) and both side surfaces of the electrode support substrate 64, and both ends thereof are joined to both ends of the interconnector 72. The solid electrolyte layer 68 is disposed so as to cover the entire fuel electrode layer 66, and both ends thereof are joined to both ends of the interconnector 72. The oxygen electrode layer 70 is disposed on the main part of the solid electrolyte layer 68, that is, on the portion covering the other surface of the electrode support substrate 64, and is positioned to face the interconnector 72 with the electrode support substrate plate 64 interposed therebetween. Yes.

  A current collecting member 76 is disposed between adjacent cells 62 in the cell stack 60a, and connects the interconnector 72 of one cell 62 and the oxygen electrode layer 70 of the other cell 62. Current collecting members 76 are disposed on both ends of the cell stack 60a, that is, on one side and the other side of the cell 62 positioned at the upper end and the lower end in FIG. Electric power extraction means (not shown) is connected to the current collecting members 76 located at both ends of the cell stack 60a, and the electric power extraction means is the front heat insulation wall 10, the rear heat insulation wall 11 or the lower heat insulation wall of the housing 2. The material 6 extends outside the housing 2. If desired, the cell stacks 60a, 60b, 60c and 60d are connected in series with each other by appropriate connection means instead of disposing the power extraction means in each of the cell stacks 60a, 60b, 60c and 60d. Common power extraction means may be provided for the cell stacks 60a, 60b, 60c and 60d.

  More specifically about the cell 62, the electrode support substrate 64 is gas permeable to allow fuel gas to permeate to the anode layer 66, and is also conductive to collect current through the interconnector 72. Can be formed from a porous conductive ceramic (or cermet) that satisfies such requirements.

  In order to manufacture the cell 62 by co-firing with the fuel electrode layer 66 and / or the solid electrolyte layer 68, it is preferable to form the electrode support substrate 64 from the iron group metal component and the specific rare earth oxide. In order to provide the required gas permeability, it is preferable that the open porosity is in the range of 30% or more, in particular 35 to 50%, and the conductivity is also 300 S / cm or more, in particular 440 C / cm or more. Is preferred.

The fuel electrode layer 66 can be formed of a porous conductive ceramic, for example, ZrO ₂ (referred to as stabilized zirconia) in which a rare earth element is dissolved and Ni and / or NiO.

The solid electrolyte layer 68 has a function as an electrolyte for bridging electrons between electrodes, and at the same time needs to have a gas barrier property in order to prevent leakage between fuel gas and air. In general, it is formed from ZrO ₂ in which ₃ to 15 mol% of a rare earth element is dissolved.

The oxygen electrode layer 70 can be formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. The oxygen electrode layer 70 is required to have gas permeability, and the open porosity is preferably 20% or more, particularly preferably in the range of 30 to 50%.

Although the interconnector 72 can be formed from a conductive ceramic, it needs to have a reduction resistance and an oxidation resistance in order to come into contact with a fuel gas and air that may be hydrogen gas. A perovskite oxide (LaCrO ₃ oxide) is preferably used. The interconnector 72 must be dense in order to prevent leakage of fuel gas passing through the fuel gas passage 74 formed in the electrode support substrate 64 and air flowing outside the electrode support substrate 64, and is 93% or more. In particular, it is desired to have a relative density of 95% or more.

  The current collecting member 76 can be composed of a member having an appropriate shape formed of a metal or alloy having elasticity, or a member obtained by adding a required surface treatment to a felt made of metal fiber or alloy fiber.

  Continuing the description with reference to FIG. 4, the power generation unit 56 a also includes a reforming case 78 a that is preferably a rectangular shape (or a cylindrical shape) that extends elongated in the front-rear direction above the cell stack 60 a. ing. One end, that is, the upper end of the fuel gas supply pipe 80a is connected to the front surface of the reforming case 78a.

  The fuel gas supply pipe 80a extends downward, then curves and extends rearward, and the other end of the fuel gas supply pipe 80a is connected to the front surface of the fuel gas case 58a. One end of a reformed gas supply pipe 82a is connected to the rear surface of the reforming case 78a. The to-be-reformed gas supply pipe 82 a extends downward from the reforming case, and extends under the housing 2 and out of the housing 2.

  The to-be-reformed gas supply pipe 82a is connected to a to-be-reformed gas supply source (not shown) which may be a hydrocarbon gas such as city gas, and is connected to the reforming case 78a through the to-be-reformed gas supply pipe 82a. A gas to be reformed is supplied. An appropriate reforming catalyst for reforming the fuel gas into a hydrogen-rich fuel gas is accommodated in the reforming case 78a.

  In the illustrated embodiment, the reforming case 78a is connected to the fuel gas case 58a via the fuel gas supply pipe 80a and is held in a required position by this, but if necessary, the two-dot chain line in FIG. For example, an appropriate support member 84a can be provided between the lower surface of the reformed gas supply pipe 82a and the lower surface or rear surface of the rear end portion of the fuel gas case 58a.

  Referring to FIG. 3, the power generation unit 56c is substantially the same as the power generation unit 56a described above, and the power generation units 56b and 56d are disposed in the front-rear direction opposite to the power generation units 56a and 56c. Fuel gas supply pipes (not shown) connecting the quality cases 78b and 78d and the fuel gas cases 58b and 58d are arranged on the rear side, and the reformed gas supply pipes 82b and 82d are located downward from the reforming case. It extends under the housing 2 and extends out of the housing 2.

  In the fuel cell assembly as described above, the gas to be reformed is supplied to the reforming cases 78a, 78b, 78c and 78d via the gas to be reformed supply pipes 82a, 82b, 82c and 82d, and the reforming case 78a. , 78b, 78c and 78d, the fuel defined in the fuel gas cases 58a, 58b, 58c and 58d through the fuel gas supply pipes 80a, 80b, 80c and 80d after being reformed into hydrogen-rich fuel gas. It is supplied to the gas chamber and then supplied to the cell stacks 60a, 60b, 60c and 60d.

In each of the cell stacks 60a, 60b, 60c and 60d, at the oxygen electrode,
1 / 2O ₂ + 2e ⁻ → O ²⁻ (solid electrolyte)
The electrode reaction of
O ²⁻ (solid electrolyte) + H ₂ → H ₂ O + 2e ⁻
The electrode reaction is generated and power is generated.

  Fuel gas and air that have flown upward from the cell stacks 60a, 60b, 60c and 60d without being used for power generation are ignited by an ignition means (not shown) disposed in the power generation / combustion chamber 12 at the time of startup. It is ignited and burned. As is well known, the power generation / combustion chamber 12 has a high temperature of, for example, about 1000 ° C. due to power generation in the cell stacks 60a, 60b, 60c and 60d, and also due to combustion of fuel gas and air. The reforming cases 78a, 78b, 78c and 78d are disposed in the power generation / combustion chamber 12, and are positioned immediately above the cell stacks 60a, 60b, 60c and 60d, and are directly heated by the combustion flame. Thus, the high temperature generated in the power generation / combustion chamber 12 is effectively used for reforming the reformed gas.

  The combustion gas generated in the power generation / combustion chamber 12 flows into the discharge passage 30 from the discharge opening 42 formed in the heat exchanger 24, and flows through the discharge passage 30 extending in a zigzag shape. 50 is discharged through a discharge passage defined between the outer cylinder member 52 and the inner cylinder member 54. When the combustion gas flows through the discharge path in the double cylinder 50, air flows through the inflow path in the double cylinder 50, and heat exchange is performed between the combustion gas and air.

  Further, when the combustion gas is caused to flow in the exhaust passage 30 of the heat exchanger 24 in a zigzag manner, the air is caused to flow so as to face the inflow passage 32 of the heat exchanger 24 in a zigzag manner. Thus, heat is effectively exchanged between the combustion gas and air to preheat the air.

  When part or all of the cell stacks 60a, 60b, 60c and 60d deteriorates due to power generation over a long period of time, the front heat insulation wall 10 or the rear heat insulation wall 11 of the housing 2 is detached or opened. Part or all of the power generation units 56 a, 56 b, 56 c and 56 d are taken out from the housing 2.

  Then, replace some or all of the power generation units 56a, 56b, 56c and 56d with new ones, or only the cell stacks 60a, 60b, 60c and 60d in some or all of the power generation units 56a, 56b, 56c and 56d. May be replaced with a new one and mounted again at a required position in the housing 2. Even when it is necessary to replace the reforming catalyst accommodated in the reforming cases 78a, 78b, 78c and 78d in some or all of the power generation units 56a, 56b, 56c and 56d, the power generation units 56a, 56b , 56c and 56d are removed from the housing 2, and the reforming cases 78a, 78b, 78c and 78d themselves in the power generation units 56a, 56b, 56c and 56d are replaced with new ones or reforming cases. Only the reforming catalyst in 78a, 78b, 78c and 78d may be replaced with a new one.

  In order to be able to perform the replacement of the reforming catalyst in the reforming cases 78a, 78b, 78c and 78d sufficiently easily, a part of the reforming cases 78a, 78b, 78c and 78d can be opened and closed if desired. It can be put on the door.

  On the other hand, air is supplied to the inflow path 32 of the heat exchanger 24 through the inflow path defined in the inner cylinder member 54 of the double cylinder 50, and is preheated (heated) through the heat exchanger 24. Is temporarily stored in the air chamber 16 and supplied between the cell stacks of the combustion / power generation chamber 12 through the air introduction pipe 22. At this time, the air introduction pipe 22 passes through the combustion gas atmosphere that burns near the fuel gas passage 74 at the upper end of the fuel cell 62 of the cell stack 60. Accordingly, the preheated air in the air chamber 16 is further heated in the combustion region above the cell stack 60, and the air heated to a high temperature is supplied to the cell.

  During normal operation, air preheated by the heat exchanger 24 is introduced into the air chamber 16, and air is introduced from the air chamber 16 into the combustion / power generation chamber 12 using the air introduction pipe 22. When the temperature rises more than expected, the low-temperature air that has passed through the low-temperature gas supply pipe 18 that does not pass through the heat exchanger 24 is introduced into the air chamber 16 and preheated through the heat exchanger 24. And the air temperature of the air chamber 16 is reduced to some extent. By supplying this air between the power generation chambers 12, that is, between the cell stacks, air having a lower temperature than that during normal operation is introduced between the cell stacks. Therefore, a good fuel cell assembly that can appropriately control the temperature in the power generation chamber is provided.

  Moreover, since the air temperature in the air chamber 16 is mixed with the outside air supplied from the low temperature gas supply pipe 18 and the air preheated through the heat exchanger 24, the air temperature is not as low as room temperature. Even if the fuel cell 60 is supplied to the hot fuel cell 60, it is possible to avoid problems such as cracks and thermal shock destruction of the fuel cell 60, so that the function deterioration of the entire fuel cell power generation system can be suppressed and the life can be extended. .

  Furthermore, by supplying the supply of the low temperature gas from the low temperature gas supply pipe 18 toward the center of the opening of the air supply pipe 22, the air heated from the heat exchangers on both sides is further directed to the center of the opening. The air supplied through the air supply pipe 22 to the center of the cell assembly that is most easily heated can be at the lowest temperature, and the temperature can be increased as the distance from the center increases. can do.

  In the fuel cell assembly of the present invention, the heat storage wall 44a, the left heat storage wall 44b, the front heat storage wall 44c and the rear heat storage wall 44d, the lower heat storage wall 44e, the upper heat insulation are provided in the housing 2 and around the cell assembly. By disposing the wall 44f on the outer surface of the housing 2, the upper heat insulating wall 4, the lower heat insulating wall 6, the right heat insulating wall 8, the left heat insulating wall 9, the front heat insulating wall 10, and the rear heat insulating wall 11 are arranged. Can be effectively stored together with the heat storage wall and the heat insulating material, and in the fuel cell assembly for distributed power generation, during partial load operation with less heat generation In this case, the power generation temperature can be effectively maintained.

  In other words, the fuel cell assembly for distributed power generation is small because the power generation amount is small, and is self-sustaining in the normal operation and generates power effectively. However, if the power generation amount is reduced by reducing the fuel gas amount, In the present invention, the heat is effectively confined in the housing by the heat insulating wall, the high-temperature heat in the steady operation is absorbed by the heat storage wall, the partial load operation is performed, and the heat generation amount is reduced. When the temperature decreases, heat can be dissipated and the temperature inside the housing can be effectively maintained.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to such embodiments, and various modifications and corrections can be made without departing from the scope of the present invention. It goes without saying that this is possible.

  For example, the present invention has been described in relation to a fuel cell assembly having a specific reforming case above the cell stack. However, the present invention can be applied even when the reforming case is not located above the cell stack. I can do it. Moreover, the case where a reforming case is not provided in a housing may be sufficient.

  Further, in the above embodiment, a case has been described in which low temperature gas supply means is provided in the air chamber and air is supplied to the outer surface of the fuel cell by the air supply pipe. However, the present invention provides the inside of the fuel cell by the air supply pipe. Of course, air may be supplied to the air. In this case, it goes without saying that an air electrode is formed inside the fuel cell and a fuel electrode is formed outside.

  Further, in the above embodiment, an example in which the low temperature gas supply means is provided in the air chamber has been described. However, it is of course possible to provide the low temperature gas supply means in the fuel gas chamber and cool the fuel cell with the fuel gas. It is.

  Furthermore, although the case where fuel gas and air react and burn above the fuel battery cell has been described in the above embodiment, the present invention may of course not burn.

Sectional drawing which shows suitable embodiment of the fuel cell assembly of this invention. The top view of FIG. FIG. 2 is a perspective view showing a power generation unit assembly used in the fuel cell assembly of FIG. 1. The perspective view which shows the electric power generation unit of FIG. Sectional drawing which shows the cell stack of FIG.

Explanation of symbols

2: Housing 4, 6, 8, 9, 10, 11: Thermal insulation wall 12: Power generation / combustion chamber 16: Air chamber (gas chamber)
18: Low temperature gas supply means 22: Air supply pipe (gas supply pipe)
24: heat exchangers 44a, 44b, 44c, 44d, 44e, 44f: heat storage walls 56a, 56b, 56c and 56d: power generation units 58a, 58b, 58c and 58d: fuel gas cases 60a, 60b, 60c and 60d: cell stacks 62: Fuel cell 78a, 78b, 78c and 78d: reforming case

Claims (7)

A plurality of fuel cells are housed in a housing, and a heat shield member is disposed in the housing, around the cell assembly of the fuel cells, and on the outer surface of the housing. Fuel cell assembly. 2. The fuel cell assembly according to claim 1, wherein a heat shield member is disposed in the housing so as to surround the cell assembly. 3. The fuel cell assembly according to claim 1, wherein the heat shield member arranged in the housing is made of a heat storage material, and the heat shield member arranged on the outer surface of the housing is made of a heat insulating material. The fuel cell assembly according to any one of claims 1 to 3, wherein a gas flow path is disposed between the heat shield members inside and outside the housing. The fuel according to any one of claims 1 to 4, wherein a combustion gas discharge channel and a gas supply channel are arranged between the heat shield members inside and outside the housing to constitute a heat exchange part. Battery assembly. 6. The fuel cell assembly according to claim 1, wherein the density of the heat storage material is larger than that of the heat insulating material. 7. The fuel cell assembly according to claim 1, wherein the fuel cell assembly is used for distributed power generation.

Images